In recent years, disk array apparatus with higher mounting density and higher performance has been developed. Accordingly, higher cooling performance has also been demanded in order to cope with the temperature rise due to the increase in heat generation of component parts and resulting performance deterioration.
For example, in a comparatively large disk array apparatus, a cooling method by means of high power fans (exhaust fan and air cooling fan) installed in the upper part of the apparatus has been adopted. A frequently-used cooling structure in a conventional large disk array apparatus is as follows. That is, a cooling air is taken in from front and rear surfaces and a bottom surface of the apparatus chassis by the operation of fans installed in an upper part of the apparatus, and the cooling air passes upward through a module group such as a HDD and a logic board and through the inside (duct) of the chassis and is then exhausted from the fans in the upper part of the apparatus. By this means, components in the apparatus are air-cooled.